Not really a question of grammar but of precision. "Over 40" means more than 40 and less than 50, but "almost 50" would be better if much closer to 50 than 40. If 67 members are reported, It should be exactly 67. If 67 percent, between 66.5 and 67.5 percent. If 60 percent, between 55 and 65 percent.
Your idea is correct, using numbers of the wrong precision is dishonest but commonly done. Everyone knows that 67.52 % of all statistics are bogus.